Railway-bridge



(No ModeL) I 2 Sheets-Sheet 1. J. DENNIS.

RAILWAY BRIDGE.

Patented June 9, 1885.

(No Model.) 2 sheets-sheen 2.

- J. DENNIS.

RAILWAY BRIDGE.

Patented June 9, 18.85.

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'ATENT JOHN DENNIS, OE OswEGO, N Ew roux.

RAlLwAY-BRI DGE.

SPECIFICATION forming part of .Letters Patent No, 319,798, dated June 9,1885.

Application filed May 27, 1882. Renewed September 3, 1884. (No model.)

To all whom it may concern:

Be it known that I, JOHN DENN1s,a citizen of the United States, of the city of Oswego, in the county of Oswego and State of New York, now temporarily residing at the city of Toronto, in the county of York, in the Province of Ontario, Canada, have invented certain new and useful Improvements in the Construction of vRailway-Bridges, of which the following is a specification.

The object of the invention'is to construct an extremely strong and rigid railway-bridge not susceptible to rot and having a nre-proof deck to prevent live coals falling from a loco-` motive taking effect; and it consists of a peculiar arrangement of peculiarly-constructed trusses designed to give the greatest possible strength, and arranged so that the joints are all protected from water, while the main timbers are arranged so that air will circulate freely around them.

While the principal feature in my invention consists in the peculiar arrangement of three or more separatetrusses placed below each rail, I shall first proceed to describe the construction of a single truss and afterward indicate the manner in which they are combined together to form compound trusses.

Figure l is an elevation of my improved bridge. Figs. 2 and 3 are sections at the centerl and at the end, respectively. vFigs. 4 to 15 are details of the various portions of the bridge, which it is important to have clearly shown.

In the drawings, A is the lower chord, de-l signed to rest upon the pier or posts B.

O is a central arched chord made in sectionsl securely spliced and bolted together, notches a being formed on the upper and lower faces` of the timbers bolted together to prevent any longitudinal movement of the parts sorbolted ing, as indicated in Fig. y1, from the straight or lower chord, A, to the central arched chord, G, into which they are securely boxed,

- as indicated, the diagonal braces over the piers being of heavier material vthan thebraces near the center of the bridge.

E are counter-braces extending from the top of one diagonal brace to the bottom of the next brace and placed, as indicated, so that one-half of their ends shall rest against the -diagonal braces, while the other half t, re-

spectively, against the arched and lower chords.

F are bolts extending from the arched chord O to the straight chord A, and situated outside of and parallel with each counter-brace. These bolts hold the parts securely together and complete a single truss.

G is an upper or carrying chord supported from the arched chord by the diagonal braces H. These braces, it will be noticed, extend from the outer end of the arched chord, and are designed to direct the strain of the load toward the outer side of the pier.

' The bolts I extend diagonally from the top of the upper chord between the arched chord vbraces and are designed to hold the trusses together and brace the three trusses marked 1, 2, and 3 in Fig. 2, which are formed in the manner of the truss hereinbefore described.

Wherever it becomes necessary to form a splicein the lower chord,A,I providewhat may be termed a tie-piece, 7 K, notched on its lower surface, as indicated, which notches fit into corresponding notches formed at this point on the top surface of the lower chord, A.

It being important, I should mention here that the tie-pieces should be suciently long to take in a distance between three of the main bolts F,'by which means the load on the bridge has a tendency to strengthen the splice. Bolts L are provided to secure or clamp the tiepiece to theglower chord.

In the center of the bridge, where the angle of the diagonal braces-is reversed, it is necessary to provide a cast-iron prism, M. This prism is formed substantiallyas shown in Fig.

l0, in which flgure it will-be noticed that on J lap over the tie-pieces K, upon which it is set,

The top of thistie-piece is covered with galvanized iron, the ends of which, coming against the prism M, are turned up below 'the lips/n to form a gutter and prevent any water falling oi` the lips finding its way between the prism M and the timbers upon which it is set, thereby forming a water-tight joint.

In order to still further insurea water-tight joint, I form on the top of the prism M asocket or stuing-box, p, around each of the holes through which the boltsFpass. These stuifing-boxes are lled with pitch, tar,". or other suitable composition.

In order to provide a support between the pier and the bottom chord of thebridge which will not be susceptible to dry rot, I provide a series of open posts constructed in the following manner: The sills Olie on top of the pier B', a space being left between them. Beams O', corresponding with the sillsO, areprovided below the chord A. Betwee'n'the sills O and beam O', I arrange a series of posts, P, around a short block, P'. This center block is bored out in its center and has vertical grooves cut around its outer surface to lpermit the air to pass freely between all the outer posts, arranged as described. The center block, P', does not extend to the bottom of the sills 0, so that there is a space between the bottom ofthe post and the top ofthe pier, to admit the air.

In order to exclude the moisture from the earth which abuts against the approach to the bridge, I provide a plank weather-board or apron, Q, as shown in Fig. l. This effectually protects the ends of the timbers forming thev approach to the bridge, and in the winterf` when the earth is frozen, in Vheaving of the' earth by the frost at the approach, the end of the approach is correspondingly raised, owing to the connection formed by theweather-planking, and consequently the level of the rail on the bridge will be the same as that on the embankment at the approach.

As shown in Figs. 2 and 3,the arrangement of my compound truss formingV asupport under each rail is indicated. The single trusses between thelower chord, A, and archedchord' C are arranged, as 'shown in Figs. 2 and 3, im-

mediately below the point where the rails P will beV located.

In order to brace together the compound trusses formed by the single trusses, I arrange a lseries of transverse beams, Q', on top of the arched chord (l and corresponding transverse beams on the bottom of the lower chord,

A. These transverse beams are bolted together by the bolts F, said ,transverse beams being placed at each point in the truss where the bolts pass through.

In order to stay the compound trusses thus braced together, and to prevent the swaying thereof, I make the transverse beams Q project beyond the compound trusses to the full width of the bridge to be built, and arrange diagonal braces R, as indicated in Figs. 2 and 3.

Fig. 2 represents a section of the'bridge at its center. At this point the braces R extend from the bottom of the inner truss to the outside end of-the top transverse beam Q', while the braces R' extend from the top of the inner truss to the outside of the ,bottom transverse beam Q'.

In order to complete the bridge thus constructed, I connect the upper and lower transverse beams Q by the bolts S, which spring the ends of the beams together and impart a tightening strain against the braces and trusses.

In the former part of the specification I describe the manner of connecting the carryingchord G upon the arched chord. It will of course be understood that this portion of the construction of the bridge will be erected on the lower truss after the vcomplete compound ltrusses have been put together, as herein described, and placed in position clear of the scaffold.

The deck, as indicated, is composed of narrow planking extending from side to side of the bridge, and sprung to form a curveddeck, as indicated in Figs. 2 and 3, the said form being produced in the following manner: Bolts U are put through the upper transverse beam Q', and through the hand or guard rail d in Figs. 2 and 3, which rail" is placed one foot` higher than the top of the floor of the bridge. The planks are then put in place and an iron standard,ce, is placed upon one end of said planks and against the hand or guard rail. The other end is then bent down to the desired radius and the standard on the opposite side put in position. Thepressure on the plank will embed the ends of the standard into the plank and hold them firmly in position.

In Fig. 14 a detail is shown for supporting the hand or guard rail. This post lis made of metal, and has notched or serrated ends which become embedded in the timbers when the bolts U compress the rails to the deck. These -planks'are grooved and slip-tongued together and are covered with a composition of pitch or tar and gravel, thereby forming both a water-tight and fire-proof deck, the curved form of the deck carrying any water falling on the deck clear of the bridge.

In order to prevent the lodgment of water or moisture on the deck between the track rails or stringers, I support the rail on a chair, V, constructed and arranged as follows: As shown in Figs. 4 and 5, the chair V supports the rail slightly above the deck, leaving a space between each two adjacent chairs for the purpose of permitting the water to pass freely away. In order to prevent the lodgment of water under the chair, I form on its bottom a channel or groove, u, connecting the bolt-holes. In order to permit the filling of this groove with tar or pitch, I make other holes leading into the channel, through which the tar or pitch, when in a liquid condition, may be freely poured to fill the channel and prevent owing to their IOO I'Io

length, to provide cross-braces or w'aling-tim` bers, I make the following` provision for the purpose of protecting the joints from the lodgment of water: In Figs; 6 and 7 I show an arrangement for accomplishing this pur? pose. lIn these gures, d is a metal bracket let into the post B, as shown-in Fig. .6,.and having arecess formed onvits face to receive the end of the waling-timber e. It will be noticed that a portion of the bracket let into the post B` slants outwardly to the outside of the recess receiving thel endY 'of the walingtimber e, overlapping the joint and forming a shed to conduct any water on the post B clear of the joint between Ait and the waling-timbein NVhen securing thewaling timber lor brace i to the post, I providea link or links, f, preferably placed one on each'side of the post, as shown in Fig. 7, one end of the vlink -f being connected to the post Bby a bolt passing through it and the other end of the link to the waling timber or brace by a similar bolt.

In order to prevent .any water finding its way into the bolt-hole and thereby rotting the timber 'and rusting the bolt, I enlargethe hole in the post through .which the bolt passes and provide a washer, g, to cover either end of the said hole. A recess, y', is formed on the top of the washer g, having a groove around its outer surface (similar to the chair in Fig. 4) for the .purpose of permitting liquid tar or pitch to be poured in the hole around the bolt, and thereby forming the desired seal to prevent the admission of water.

Wherever a joint is required in a horizontal timber which is exposed, I form a V-splice, as indicated in Fig. '8, and protected as shown in Fig. 9. yIn these figures it will be noticed that the washer h is embedded in the top surface of the timber immediately over the V- shaped joint, and that at each end of the washer a pin or spike point, h', is formed. This spike-point constitutesa lock for securing the ends oi' the jointed timbers together, while the V-shaped connection permits the lateral adjustment of the two timbers. In order to prevent any water finding its way below the washer or the bolt-hole, Iflll in the space above the embedded washer with tar or pitch, and in order to protect the entire suri'ace of the timbers, including the joints, I spread tar or pitch and gravel.

Wherever a vertical timber butts against a horizontal timber in an exposed position, I

-form aWater-tight joint, as shown in Fig. 13.

Instead of putting a mortise-and-tenon joint, I place a square hard wood pin in a round hole in the end of the vertical timber and bore ahole in the horizontal timber to receive its projecting point.

In order to ventilate the center of the vertical post, I bore diagonal holes 7a in the center hole of the post. These holes k permit meto pour into the center hole tar or pitch, which rills the space between the pin and hole, and also two grooves, 7c', formed on the bottom end of the vertical post, forming thereby a watertight joint.

v When the posts arranged to support the ends of the bridge are in an exposed position,I insert a semicircular piece of galvanized iron,. 03,'near the bottom of the post, and on either side of the said iron I place aplate, O2. By inserting the galvanized iron in the-semicircular form it will remain in position better than if it were straight. Thisgalvanizediron forms a shed to' receive the water trickling braces, of counter-braces, the upper end of each being set so that one-hal f shall rest against the arched chord and its other half against one of the diagonal braces, ther'lower end of the counter-brace being similarly situated against the straight lower chord and the bottom end ofthe next diagonal brace, and suitable bolts extending from the arched chord to the straight chord outside of and parallel with each counter-brace to hold the braces in position and complete the single truss, as specified.

2. In a bridge having a central arched chord braced, as described, to the bottom or lower chord which rests upon the pin, the upper or carrying chord suitably braced to the arched chord by diagonal braces extending from the outer end of the arched chord for the purpose of directing the strain of the load to the outer end of the truss, substantially as and for the purpose specified.

3. In a bridge having a central arched chord braced, as described, and the lower straight chord, and an upper or carrying chord braced to the arched chord by diagonal braces, the combination, with such chords and braces, of bolts extending diagonally from the top of the carrying-chord to the bottom of the arched chord and held in position by clamp-pieces, substantially as and for the purpose specified 4'. In a bridge in which the carrying or upper chord is braced to the lower chord, as described, so as to form a complete single truss, three or more trusses so formed placed below each rail and braced or tied together by the transverse beams, in combination with the diagonal braces R and bolts F, situated substantially as shown and described.

5. In a railway bridge provided with a curved water-proof deck, a wooden hand-rail supported by the metal standards having notched or serrated ends to fit into the handrail and deck, as described, in combination with the bolts extending from the top of the hand-rail through the standards and deck to the transverse beam, substantially as and for the purpose specified.

6. In a bridge in which the length of the ICO chords necessitates Vtheir being spliced, a tiepiece notched on its bottom surface and placed over the joint on the top edge of each chord, which chord has corresponding notches formed on its top surface, in combination with braces D E, lbearing on the tie-pieces, bolts F, arranged to strain the whole together and allow the load on the bridge to assist in strengthening the splice, substantially as and for the purpose specified.

7. In a bridge in which compound trusses are placed below each rail and bound together by transverse beams located on the top and bottom of the trusses and projecting beyond the trusses to the full width of the bridge, the combination, with such compound trusses and beams, of cross-braces extending from the top to the bottom transverse beams, which are drawn together at their outer ends by bolts S,

designed to spring the ends of the beams to# gether and impart a tightening strain against the braces and trusses, as set forth.

8. In combination with two timbers the ends of which are connected together by a V- shaped joint, a washer, h, embedded in the top surface of the timbers immediately over the V-shaped joint and having spiked ends h', to form a lock for connecting the ends of the timbers together, the spaces above the washer being filled and top surface of the timbers covered with acomposition of tar or pitch and gravel, substantially as and for the purpose specified.`

9. In a truss-bridge in which4 lthe center braces are supported on a metal prism having aprons on either end to fit over the tie-piece and stunning-boxes around the bolts, as described, curved lips formed on either side of the said prism, in combination with a galvanized-iron covering placed on top of the tiepiece supporting the prism, and having curved ends fitting below the curved lips of the prism for the purpose of forming a gutter to receive any water falling from the prism, substantially as and for the purpose specified.

10. A short center block, p', having a hole bored in its center and vertical grooves cut in its outer surface, in combination with a series of posts, p, as described, for the purpose of forming a ventilated support to the ends of the bridge, as specified. v

JOHN4 DENNIS. 

